This is the ancient housing for the Hakka community in China. Dr. Hsu, my feng shui master from Taiwan, is Hakka and introduced this to us in class before.
The feng shui for this is interesting. These structures are huge and protected the whole community. It reminded me of the European castles with tall walls and a moat around it. As you can see, they have very small windows on the outer wall, just like the castles. They could see the enemy approaching and could shoot arrows from the small openings, but the arrows couldn’t get in.